The Human Microbiome: An Invisible Spouse in Sickness and in Health

The second we are born, each of us enters a unique relationship that is going to last a lifetime. Who’s the lucky one, you ask? About 100 trillion microbes that dwell everywhere on and inside our body: the skin, the mouth, the gut. Click on the individual words in this Scientific American interactive map to explore who lives within us.

Your enemies are my enemies: The Economist describes the symbiotic relationship between us and our microbes; while we offer them shelter and raw materials, they provide nutritional services and synthesis of vitamins, as well as protection from interlopers. They also educate our immune system to discriminate between thousands of harmless species and pathogens.

Unfortunately, as in most marriages, times are not always as harmonious as we would like them to be. Disbalances in our microbiome have a striking effect on the body and have been associated with a wide variety of diseases: metabolic conditions, such as type 2 diabetes and obesity; heart disease; asthma and eczema; and even autoimmune disorders like inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), and rheumatoid arthritis.

A New York Times article explores the complexity of the human microbiome and efforts to restore order to the microbial system.

The human microbiome is unique in every person and varies from day to day. Eric Alm from MIT tracked his gut microbiome for a whole year and noticed that no day is the same in the microbial universe (see his 2012 GET Conference talk). He did so by collecting and measuring stool samples every single day. Read another New York Times article to find out about new surveys that help scientists measure and understand the microbiome.

This slideshow by David A. Relman (Stanford University) views our invisible spouse as a complex ecosystem and addresses important characteristics: diversity, stability, and resilience.